Results for “Bulletin” — Page 14

USGS1966

Hawaiian Volcano Observatory record book 1960, 1965, and 1966

The Hawaiian Volcano Observatory (HVO) record books are annual journals in which field observations of eruptive activity at Kīlauea and Mauna Loa volcanoes, on the Island of Hawaiʻi, were compiled by HVO staff for most years from 1912 through early 1966. In addition to descriptive observations, the record books also contain hundreds of annotated photographs and sketches, as well as temperature and transit measurements. When photographs are included, the camera settings and film types used are noted. The field notes, sketches, and photographs used to compile the record books provide an unparalleled record of eruptive activity and were the basis for published newspaper reports and periodic bulletins, such as the Hawaiian Volcano Observatory bulletins and The volcano letter . HVO staff also painstakingly prepared a second copy of each early record book, virtually identical to the original, complete with photographs and sketches. The original version of the record book was kept at HVO, while the duplicate went to the Hawaiian Volcano Research Association, which was created by a group of Honolulu, Hawaiʻi, businessmen to promote HVO’s work. The Hawaiian Volcano Research Association, which dissolved decades ago, held the duplicate books in Honolulu, where they were more readily accessible to the public. After 1923, HVO stopped duplicating the books—at least, no duplicate records for subsequent years have been found. During the decade of the 1940s, preparation of the record books stopped altogether. In 1952, compilation of the record books resumed and continued, with long gaps, until early 1966. Entries in these later volumes are sparse, and these books are little more than photo albums of the episodic eruptions of Kīlauea. The original record books were held at HVO and, later, at Hawai‘i Volcanoes National Park. In 1972, the original record books for the years 1912 through 1939 were transferred to the Bishop Museum, in Honolulu, for safekeeping. These record books are now stored in archival boxes at that institution (accession number 172.265). The duplicate set of record books held by the Hawaiian Volcano Research Association were bound into volumes at an unknown date and turned over to the U.S. Geological Survey. This set of record books, spanning 1912 through 1923, is now housed in the rare book room of the U.S. Geological Survey Library in Reston, Virginia (catalog number 220(950) H3d). The record books for 1952 through early 1966 remain in storage at HVO. After 1955, typed annotations were no longer placed in the record books, and only photographs, most with captions, were included. Although the volumes titled “Record Book” end with the 1955 volume, the photograph albums that followed are similar, and the record book designation is retained for simplicity. Note that the photographs in these albums were not all originally arranged in chronological order.

Hawaii↗

USGS1963

Hawaiian Volcano Observatory record book 1963

The Hawaiian Volcano Observatory (HVO) record books are annual journals in which field observations of eruptive activity at Kīlauea and Mauna Loa volcanoes, on the Island of Hawaiʻi, were compiled by HVO staff for most years from 1912 through early 1966. In addition to descriptive observations, the record books also contain hundreds of annotated photographs and sketches, as well as temperature and transit measurements. When photographs are included, the camera settings and film types used are noted. The field notes, sketches, and photographs used to compile the record books provide an unparalleled record of eruptive activity and were the basis for published newspaper reports and periodic bulletins, such as the Hawaiian Volcano Observatory bulletins and The volcano letter . HVO staff also painstakingly prepared a second copy of each early record book, virtually identical to the original, complete with photographs and sketches. The original version of the record book was kept at HVO, while the duplicate went to the Hawaiian Volcano Research Association, which was created by a group of Honolulu, Hawaiʻi, businessmen to promote HVO’s work. The Hawaiian Volcano Research Association, which dissolved decades ago, held the duplicate books in Honolulu, where they were more readily accessible to the public. After 1923, HVO stopped duplicating the books—at least, no duplicate records for subsequent years have been found. During the decade of the 1940s, preparation of the record books stopped altogether. In 1952, compilation of the record books resumed and continued, with long gaps, until early 1966. Entries in these later volumes are sparse, and these books are little more than photo albums of the episodic eruptions of Kīlauea. The original record books were held at HVO and, later, at Hawai‘i Volcanoes National Park. In 1972, the original record books for the years 1912 through 1939 were transferred to the Bishop Museum, in Honolulu, for safekeeping. These record books are now stored in archival boxes at that institution (accession number 172.265). The duplicate set of record books held by the Hawaiian Volcano Research Association were bound into volumes at an unknown date and turned over to the U.S. Geological Survey. This set of record books, spanning 1912 through 1923, is now housed in the rare book room of the U.S. Geological Survey Library in Reston, Virginia (catalog number 220(950) H3d). The record books for 1952 through early 1966 remain in storage at HVO. After 1955, typed annotations were no longer placed in the record books, and only photographs, most with captions, were included. Although the volumes titled “Record Book” end with the 1955 volume, the photograph albums that followed are similar, and the record book designation is retained for simplicity. Note that the photographs in these albums were not all originally arranged in chronological order.

Hawaii↗

USGS1965

Hawaiian Volcano Observatory record book 1963, 1964, and 1965

The Hawaiian Volcano Observatory (HVO) record books are annual journals in which field observations of eruptive activity at Kīlauea and Mauna Loa volcanoes, on the Island of Hawaiʻi, were compiled by HVO staff for most years from 1912 through early 1966. In addition to descriptive observations, the record books also contain hundreds of annotated photographs and sketches, as well as temperature and transit measurements. When photographs are included, the camera settings and film types used are noted. The field notes, sketches, and photographs used to compile the record books provide an unparalleled record of eruptive activity and were the basis for published newspaper reports and periodic bulletins, such as the Hawaiian Volcano Observatory bulletins and The volcano letter . HVO staff also painstakingly prepared a second copy of each early record book, virtually identical to the original, complete with photographs and sketches. The original version of the record book was kept at HVO, while the duplicate went to the Hawaiian Volcano Research Association, which was created by a group of Honolulu, Hawaiʻi, businessmen to promote HVO’s work. The Hawaiian Volcano Research Association, which dissolved decades ago, held the duplicate books in Honolulu, where they were more readily accessible to the public. After 1923, HVO stopped duplicating the books—at least, no duplicate records for subsequent years have been found. During the decade of the 1940s, preparation of the record books stopped altogether. In 1952, compilation of the record books resumed and continued, with long gaps, until early 1966. Entries in these later volumes are sparse, and these books are little more than photo albums of the episodic eruptions of Kīlauea. The original record books were held at HVO and, later, at Hawai‘i Volcanoes National Park. In 1972, the original record books for the years 1912 through 1939 were transferred to the Bishop Museum, in Honolulu, for safekeeping. These record books are now stored in archival boxes at that institution (accession number 172.265). The duplicate set of record books held by the Hawaiian Volcano Research Association were bound into volumes at an unknown date and turned over to the U.S. Geological Survey. This set of record books, spanning 1912 through 1923, is now housed in the rare book room of the U.S. Geological Survey Library in Reston, Virginia (catalog number 220(950) H3d). The record books for 1952 through early 1966 remain in storage at HVO. After 1955, typed annotations were no longer placed in the record books, and only photographs, most with captions, were included. Although the volumes titled “Record Book” end with the 1955 volume, the photograph albums that followed are similar, and the record book designation is retained for simplicity. Note that the photographs in these albums were not all originally arranged in chronological order.

Hawaii↗

USGS1965

Hawaiian Volcano Observatory record book 1965

The Hawaiian Volcano Observatory (HVO) record books are annual journals in which field observations of eruptive activity at Kīlauea and Mauna Loa volcanoes, on the Island of Hawaiʻi, were compiled by HVO staff for most years from 1912 through early 1966. In addition to descriptive observations, the record books also contain hundreds of annotated photographs and sketches, as well as temperature and transit measurements. When photographs are included, the camera settings and film types used are noted. The field notes, sketches, and photographs used to compile the record books provide an unparalleled record of eruptive activity and were the basis for published newspaper reports and periodic bulletins, such as the Hawaiian Volcano Observatory bulletins and The volcano letter . HVO staff also painstakingly prepared a second copy of each early record book, virtually identical to the original, complete with photographs and sketches. The original version of the record book was kept at HVO, while the duplicate went to the Hawaiian Volcano Research Association, which was created by a group of Honolulu, Hawaiʻi, businessmen to promote HVO’s work. The Hawaiian Volcano Research Association, which dissolved decades ago, held the duplicate books in Honolulu, where they were more readily accessible to the public. After 1923, HVO stopped duplicating the books—at least, no duplicate records for subsequent years have been found. During the decade of the 1940s, preparation of the record books stopped altogether. In 1952, compilation of the record books resumed and continued, with long gaps, until early 1966. Entries in these later volumes are sparse, and these books are little more than photo albums of the episodic eruptions of Kīlauea. The original record books were held at HVO and, later, at Hawai‘i Volcanoes National Park. In 1972, the original record books for the years 1912 through 1939 were transferred to the Bishop Museum, in Honolulu, for safekeeping. These record books are now stored in archival boxes at that institution (accession number 172.265). The duplicate set of record books held by the Hawaiian Volcano Research Association were bound into volumes at an unknown date and turned over to the U.S. Geological Survey. This set of record books, spanning 1912 through 1923, is now housed in the rare book room of the U.S. Geological Survey Library in Reston, Virginia (catalog number 220(950) H3d). The record books for 1952 through early 1966 remain in storage at HVO. After 1955, typed annotations were no longer placed in the record books, and only photographs, most with captions, were included. Although the volumes titled “Record Book” end with the 1955 volume, the photograph albums that followed are similar, and the record book designation is retained for simplicity. Note that the photographs in these albums were not all originally arranged in chronological order.

Hawaii↗

USGS1994

Locating and managing peninsulas for nesting ducks

The purpose of this extension bulletin is to guide the management of nesting ducks on peninsulas on public and private lands. Managing peninsulas for ducks is a relatively new strategy that was developed in the grassland region of western North America. Information contained in this bulletin is primarily from studies conducted by biologists working at the Northern Prairie Wildlife Research Center.

Report↗

USGS1986

Effect of height and orientation (microclimate) on geomorphic degradation rates and processes, late-glacial terrace scarps in central Idaho

Skip Nav Destination RESEARCH ARTICLE | JULY 01, 1986 Effect of height and orientation (microclimate) on geomorphic degradation rates and processes, late-glacial terrace scarps in central Idaho KENNETH L. PIERCE ; STEVEN M. COLMAN Author and Article Information GSA Bulletin (1986) 97 (7): 869–885. https://doi.org/10.1130/0016-7606(1986)97<869:EOHAOM>2.0.CO;2 Article history Standard View 2.0.CO;2" data-doctype="contentPdf" data-article-id="188507" data-mce-href="https://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/97/7/869/3434736/i0016-7606-97-7-869.pdf"> Open the PDF for in another window Cite Share Icon Share Permissions Abstract Terrace scarps can serve as a nearly ideal natural laboratory for the study of the evolution of slopes. This paper examines the effects of scarp size (height) and orientation (microclimate) by keeping constant variables such as age, lithology, and regional climate. If a scarp degrades as a closed system, and downslope movement is directly proportional to surface gradient , the evolution of the scarp is modeled by the diffusion equation. For a group of scarps of same age and known starting angle, the diffusion-equation model predicts the relation between maximum scarp angle (𝛉) and scarp height ( h ). Late Pleistocene terrace scarps now as steep as 33.25°, as well as measured angles of repose for sand and gravel, require a starting angle as steep as 33.5°. For latest Pleistocene Idaho and Utah scarps, as h increases, 𝛉 is gentler (more degraded) than modeled by the diffusion equation with a constant rate coefficient. The degradation-rate coefficient ( c ) increases tenfold with scarp height; it should not change with scarp height if downslope movement is solely determined by surface gradient (to the first power). Soil wash appears to be responsible for this departure from the diffusion-equation model, for transport rate by soil wash is a function of scarp size (height). South-facing scarps are less vegetated and more degraded than north-facing scarps. For scarps 2 m high, the degradation rate ( c *) on S-facing scarps is 2 times that on N-facing scarps; for 10-m scarps, it is 5 times. The observed dependence of the rate coefficient c * on scarp height can be removed by normalizing c * to values for west-facing scarps of the same height. The residual c * values calculated by this method correlate well with differences in incident solar radiation resulting from the different scarp orientations and maximum gradients. This correlation demonstrates the importance of orientation on slope processes and their rates through the differences in freeze-thaw cycles, soil moisture, and vegetative cover. Scarp morphology may be used to estimate age, if one accounts for the effects of climate and for scarp height, orientation, and lithology. For example, using the dated Bonneville shoreline scarps for calibration and comparing only scarps of equal height, we estimate the Drum Mountains fault scarps to be 9,000 yr old. This age is about twice that produced by previous diffusion-equation calculations that have not accounted for the height as we have here, but it is the same as independent geologic estimates of their age.

Idaho↗

USGS2016

Editor’s note

Heavy metal contamination at shooting ranges is well documented (e.g., Heier et al. 2009; Islam et al. 2016). Primarily lead, but also copper, zinc, and antimony often occur at high concentrations in shooting range soils; cadmium, nickel, silver, and arsenic may also be present (Cao et al. 2003; Islam et al. 2016). These metals represent a potential threat to human health and wildlife. Although much of the lead and other metals remains in the soil (Clausen et al. 2011), some metals can also contaminate groundwater and surface water and thereby threaten aquatic life (Heier et al. 2009). Results of a study published in the current issue of the Bulletin of Environmental Contamination and Toxicology (Stauffer et al. 2017) indicate that mercury contamination may also be an issue at shooting ranges, which has not been previously reported.

Bulletin of Environmental Contamination and Toxico↗

USGS1953

Biologists in the field of wildlife conservation

We often hear comments such as "people are funny" and "one meets the strangest people!" Such sage remarks are not infrequently directed towards biologists, particularly those engaged in one of the many phases of wildlife conservation work. Bulletins of the "love life" of the raccoon or frog, and biologists who, for one reason or another, count the "whiskers" on a fox squirrel are held up for ridicule or dismissed with a shake of the head or a shrug of the shoulder and termed "batty."

AIBS Bulletin↗

USGS1893

Insect fauna of the Rhode Island coal field

Some years ago Rev. Edgar F. Clark, then of Providence, Rhode Island, discovered in the Coal-measures of the neighborhood of that city the wing of a cockroach. This stimulated further search by others as well as himself, with the result of finding a fair number and variety of insect types, some of special interest. Most of the discoveries have been made by Mr. Clark (part of them while in the service of the U. S. Geological Survey) and by two young inen of Providence, Messrs. Frederick P. Gorham and Herbert Scholfield, who have been particularly encouraged in their work by Prof. A. S. Packard, of Brown University. All of the specimens have passed under my eye and are herewith described and figured. They consist of Anthracomartus, the first discovered Arachnid in the Carboniferous deposits of the eastern United States; a new genus of Neuropteroidea and one of Protophasmida, each very different from any forms hitherto found in this country, but rather allied to some from the rich Carboniferous beds of Commentry, in France, presenting new features of alliance between the Carboniferous faunas of Europe and America; and a number of cockroaches, all represented by their wings alone. These last show considerable variety of form, both known subfamilies of Paloblattarioe being present, including three genera and nearly a dozen species, the genus Etoblattina, which is the prevalent Carboniferous type the world over, being represented by at least eight species, which again show unusual diversity in size, form, and distribution of the nervules that form the framework of the wing. All the species without exception are new to science and unknown elsewhere. A few additional stones have been submitted to me containing what are apparently parts of the wings of cockroaches, but they are too fragmentary to be of the least value. Nothing more can be said than that they are or may be portions of such wings. It is hoped that the publication of this bulletin will excite further exploration and result in more extended discoveries.

Rhode Island↗

USGS1985

Computer-assisted map projection research

Computers have opened up areas of map projection research which were previously too complicated to utilize, for example, using a least-squares fit to a very large number of points. One application has been in the efficient transfer of data between maps on different projections. While the transfer of moderate amounts of data is satisfactorily accomplished using the analytical map projection formulas, polynomials are more efficient for massive transfers. Suitable coefficients for the polynomials may be determined more easily for general cases using least squares instead of Taylor series. A second area of research is in the determination of a map projection fitting an unlabeled map, so that accurate data transfer can take place. The computer can test one projection after another, and include iteration where required. A third area is in the use of least squares to fit a map projection with optimum parameters to the region being mapped, so that distortion is minimized. This can be accomplished for standard conformal, equalarea, or other types of projections. Even less distortion can result if complex transformations of conformal projections are utilized. This bulletin describes several recent applications of these principles, as well as historical usage and background.

Bulletin↗

USGS1989

Methods for sampling and inorganic analysis of coal

Methods used by the U.S. Geological Survey for the sampling, comminution, and inorganic analysis of coal are summarized in this bulletin. Details, capabilities, and limitations of the methods are presented.

Bulletin↗

USGS1885

Notes on the stratigraphy of California

A complete examination of the Coast Ranges of California can hardly be undertaken by the Geological Survey for some years to come, consistently with the plans at present formed. The detailed study of certain small areas in these ranges, however, raised a number of questions as to the age and stratigraphical relations of the various series of beds, which it seemed necessary to answer as well as circumstances permitted. Having reached certain conclusions, for the most part on structural grounds, it became indispensable for me to obtain the co-operation of an expert paleontologist. At my solicitation, and with the approval of the director, Dr. C. A. White consented to visit the field with me. He passed several months of the summer of 1884 in studying my collections and the occurrence of fossils in place with reference to the points at issue. His results appear in Bulletin No. 15, that and this being complementary to one another. I had the great satisfaction of finding that Dr. White was led from a purely paleontological position to conclusions entirely accordant with those at which I had already arrived on structural grounds. His long experience as a general geologist also made his agreement with me as to the structural indications a welcome confirmation of my opinions. These studies, in conjunction with many observations made by earlier workers on the Pacific Coast, particularly those of the State Geological Survey of California, under Prof. J. D. Whitney, have led to some seemingly well established general conclusions of interest. The more purely geological results will be presented in the following pages, in the imperfect form in which alone it will be possible to give them until an immense amount of additional work shall have been done.

California↗

USGS1992

Geologic studies in Alaska by the U.S. Geological Survey, 1990

This collection of papers continues the annual series of U.S. Geological Survey (USGS) reports on geologic investigations in Alaska. From 1975 through 1988, the series was published as USGS circulars. The first of these appeared under the title "The United States Geological Survey in Alaska: Accomplishments during 1975," and the series continued to the last annual circular entitled "Geologic studies in Alaska by the U.S. Geological Survey during 1987," which reflects a title change made in 1986. This 1990 volume continues the bulletin format started in 1988. As in 1989, this volume separates shorter contributions as Geologic Notes from more extensive Articles. This 1990 volume of 18 Articles and 4 Geologic Notes represents the broad range of USGS research activities carried out in Alaska over the past few years. These studies include topics on mineral and other resources such as gold (Y eend), platinum-group elements (Cathrall and Antweiler), coal (Roberts, Stricker, and Affolter), and petroleum (Howell, Bird, and others). Many other investigations provide background geochemical (Kilburn, Box, and others) and geologic data needed for resource evaluation as well as for determining the general geologic framework of Alaska, as in stratigraphic, sedimentologic, and paleontologic and radiometric age studies (Blodgett, Clough, and others; Box and Elder; Dickinson and Skipp; Marincovich and Moriya; McLean and Stanley; Stanley, Flores, and Wiley; Roeske, Pavlis, and others); geophysics (Sampson, Labson, and Long); structure and tectonic evaluations (Bradley and Kosky; Clendenen, Sliter, and Byrne; Karl; Csejtey; Howell, Johnsson, and others); and geomorphic and late Quaternary studies (Carter and Hillhouse; Galloway, Huebner, and others; McGimsey, Richter, and others; Nelson and Carter). These studies span nearly the entire State from the North Slope and Brooks Range to interior, southwestern, and south-central Alaska (fig. 1). Two bibliographies (White) at the end of the volume list (1) reports about Alaska in USGS publications released in 1990 and (2) reports about Alaska by USGS authors in publications outside the USGS in 1990. A bibliography and index of papers in past USGS circulars that are devoted to geologic research and accomplishments in Alaska (1975 to 1986) is published as USGS Open-File Report 87-420.

Alaska↗

USGS1993

Geologic studies in Alaska by the U.S. Geological Survey, 1992

This collection of 19 papers continues the annual series of U.S. Geological Survey reports on the geology of Alaska. The contributions, which include full-length Articles and shorter Geologic Notes, cover a broad range of topics including dune formation, stratigraphy, paleontology, isotopic dating, mineral resources, and tectonics. Articles, grouped under four regional headings, span nearly the entire State from the North Slope to southwestern, south-central, and southeastern Alaska (fig. 1). In the section on northern Alaska, Galloway and Carter use new data on dune morphology and radiocarbon ages from the western Arctic Coastal Plain to develop a late Holocene chronology of multiple episodes of dune stabilization and reactivation for the region. Their study has important implications for climatic changes in northern Alaska during the past 4,000 years. In two papers, Dumoulin and her coauthors describe lithofacies and conodont faunas of Carboniferous strata in the western Brooks Range, discuss depositional environments, and propose possible correlations and source areas for some of the strata. Schenk and Bird propose a preliminary division of the Lower Cretaceous stratigraphic section in the central part of the North Slope into depositional sequences. Aleinikoff and others present new U-Pb data for zircons from metaigneous rocks from the central Brooks Range. Karl and Mull, reacting to a proposal regarding terrane nomenclature for northern Alaska that was published in last year's Alaskan Studies Bulletin, provide a historical perspective of the evolution of terminology for tectonic units in the Brooks Range and present their own recommendations.

Alaska↗

USGS2003

Contributions to Industrial-Minerals Research

Contributions to Industrial-Minerals Research, an ongoing series of U.S. Geological Survey (USGS) Bulletin chapters, presents research strategies, results, and updates of investigations of industrial minerals by USGS scientists and cooperators. Industrial minerals are defined as valuable nonmetallic, nonfuel geologic materials, generally rocks or minerals, used in a wide range of construction and industrial applications-for example, sand, gravel, and crushed rock used as aggregate for construction; limestone used for cement; phosphate for fertilizers and insecticides; and diatomite used for filtration, fillers, and abrasives. The term also comprises some processed materials, such as cement and metallic compounds with major utilization in nonmetallic forms. For example, titanium is commonly grouped with industrial minerals because more than 90 percent of it is sold and utilized in the form of the oxide (TiO2) rather than as Ti metal. Other metals and metallic compounds commonly grouped with industrial minerals include Mn, Cr, Fe oxides, and rare-earth elements (REEs).

Bulletin↗

USGS2003

Geoenvironmental Investigations of the Humboldt River Basin, Northern Nevada

Northern Nevada is one of the world's foremost regions of gold production. The Humboldt River Basin (HRB) covers 43,500 km2 in northern Nevada (Crompton, 1995), and it is home to approximately 18 active gold and silver mines (Driesner and Coyner, 2001) among at least 55 significant metallic mineral deposits (Long and others, 1998). Many of the gold mines are along the Carlin trend in the east-central portion of the HRB, and together they have produced 50 million ounces of gold from 1962 (when the Carlin mine first opened) through April 2002 (Nevada Mining Association, 2002). Mining is not new to the region, however. Beginning in 1849, mining has taken place in numerous districts that cover 39 percent of the land area in the HRB (Tingley, 1998). In addition to gold and silver, As, Ba, Cu, Fe, Hg, Li, Mn, Mo, Pb, S, Sb, V, W, Zn, and industrial commodities such as barite, limestone, fluorite, sand and gravel, gypsum, gemstones, pumice, zeolites, and building stone, have been extracted from the HRB (McFaul and others, 2000). All papers within this series of investigations can be found as lettered chapters of USGS Bulletin 2210, Geoenvironmental Investigations of the Humboldt River Basin, Northern Nevada. Each chapter is available separately online. The data and software utilized in this product (Chapter F) permit the user to view and analyze the geographic relationships among chemistry of stream sediments and surface waters, geology, and various cartographic base information such as but not limited to cities, county boundaries, and land ownership. Data for this product were compiled and or produced as part of a mineral and environmental assessment of the Humboldt River basin conducted by the U.S. Geological Survey between 1995 - 2000.

Bulletin↗

USGS1904

The United States Geological Survey, its origin, development, organization, and operations

The United States Geological Survey, in the Department of the Interior, was created by act of Congress approved March 3, 1879, so that March 3, 1904, marks the completion of the twenty-fifth year of its existence. The quarter-century anniversary happens to fall near the date set for the opening of the Louisiana Purchase Exposition at St. Louis, at which the Survey will make an exhibit. It is hoped that many of the people of this country will be interested in that exhibit, and, in connection therewith, it has been thought desirable to place before the public, by means of a small bulletin, an account of the organization and work of the Survey and the results it has achieved.

Bulletin↗

USGS1885

Observations on the junction between the Eastern sandstone and the Keweenaw series on Keweenaw Point, Lake Superior

Although the copper-bearing rocks of Lake Superior and the adjoining formations have attracted the attention of geologists for fifty years past, there are yet remaining unsolved very many problems with regard to them. We have ourselves, indeed, written at some length with regard to these rocks, and one of us has even attempted a general account of the series as a whole. In the course of our investigations each of us has been obliged to turn away from very many tempting problems in structure and genesis, where there was every promise of successful solutions if only the element of time had not been lacking. Not the least important among the problems which we have hitherto been thus obliged to pass by is that of the exact nature of the structural details at the contact line between the Keweenaw Series and the so-called Eastern Sandstone. This contact line one of us had already examined sufficiently to satisfy himself of the general relations of the two formations concerned, but he had not been able to go further than this. Recently, however, the opportunity has offered for us to make together some additional observations on this line of contact, with results that have proved to be of so conclusive a nature that we think it well to publish them in the form of a bulletin. In what follows the several places at which this junction has been studied by us are taken up in order from east to west. Preceding our own descriptions of each one of these points, we give the descriptions of others, so far as we are acquainted with them. Following these detailed descriptions, we then give an account and a discussion of the various views which have been held with regard to the relations of the two formations concerned, and then close with our own conclusions on this subject, as also in general upon the origin of the phenomena observed along the contact line.

Michigan↗